tetris pcb giving a black screen. Not a monitor issue.

ryandimx

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tetris pcb giving a black screen. Not a monitor issue.

Tetris pcb having issues. Totally black screen. I get a sound when I add credits but not game sounds when I press start. Leds on the board are still coming on ps voltage tests fine on the ps and at the harness. Other pcbs tested in the cab show the monitor is working fine. Board tested in other working cabinets same results.
 

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Interesting problem! Looks like your video section (going from VRAM to video signals) is ok according to the test mode, so that rules out about 8 ICs.

If you have a EPROM reader, check that the 28 pin ROM @ 35A has a good image on it - this is the Tetris Graphics ROM IC; I suggest dump its contents and compare against romident.

Do you have an o-scope by chance?
I'm wondering if the SOS chip is behaving for you, the other issue could be some of the bus controller chips that shuttle the image data to the VRAM (6116).
The other thing I wonder is if your SLAPSTIC@F40 went bad, maybe swap with another board if you have one?

What speed 6116 did you find?

Please report your findings, and Good luck!
 
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IIRC Tetris used a lot PAL/GALs which might make this more difficult if it's one of those. As stated earlier, the video *seems* to be fine. 6116 is basically a standard 2kx8 SRAM but make sure you get the right speed or higher (i.e. the access time needs be shorter).

Scope + schematics would allow you to rule areas out quicker.

Keep us posted!
 
Scope + schematics would allow you to rule areas out quicker.

No schematics for Atari Tetris have appeared so far, just FYI. ieure and several other folks helped me reverse engineer a lot of the video components on the thread ieure linked above.
 
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No schematics for Atari Tetris have appeared so far, just FYI. ieure and several other folks helped me reverse engineered a lot of the video components on the thread ieure linked above.

they never will appear. no schematics exist for tetris. ever. and never will. good luck with that!
 
When I switch to test mode, test mode will come up

I have the exact same problem with my Tetris PCB. It was working yesterday and now it "boots" to a black screen. All tests pass in test mode.

Here is a video of a logic probe on the reset of the CPU. As you can see it resets every few seconds. For some reason the watchdog circuit seems to be resetting the board.

Did you ever get anywhere fixing yours?

 
It's alive! I put a jumper across the WD-DIS (watch dog disable) pins and the game seems to run fine. Is it worth debugging the WD circuit at this point? Any suggestions as to where to start?
 
If you want to learn, it's a good experience, please document the process you go through figuring it out if you do...

If the rest of the circuit is working ok, probably leaving the WD disabled won't hurt. It was really designed to catch occasional bugs in the code that would wedge up a cabinet in the arcade.
 
If you want to learn, it's a good experience, please document the process you go through figuring it out if you do...

If the rest of the circuit is working ok, probably leaving the WD disabled won't hurt. It was really designed to catch occasional bugs in the code that would wedge up a cabinet in the arcade.

Hmm, I removed the jumper on the WD disable and the game runs fine again. Looks to be an intermittent issue. I'll have to wait to see if it returns. Maybe a bad solder joint...
 
A wild Tetris Schematics has appeared!


My travel with Atari Tetris has ended - the family prefer the 4 player couch version of Tetris Puyo Puyo on Switch.

I think the only classic Tetris version I'd consider owning in the garcade is the head to head cocktail, but good luck finding one of those out there for less than an arm and a leg.
 
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